001    /**
002     * Copyright (c) 2000-2012 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.servlet.filters.etag;
016    
017    import com.liferay.portal.kernel.servlet.BufferCacheServletResponse;
018    import com.liferay.portal.kernel.util.ParamUtil;
019    import com.liferay.portal.servlet.filters.BasePortalFilter;
020    
021    import java.nio.ByteBuffer;
022    
023    import javax.servlet.FilterChain;
024    import javax.servlet.http.HttpServletRequest;
025    import javax.servlet.http.HttpServletResponse;
026    
027    /**
028     * @author Eduardo Lundgren
029     * @author Brian Wing Shun Chan
030     * @author Raymond Augé
031     * @author Shuyang Zhou
032     */
033    public class ETagFilter extends BasePortalFilter {
034    
035            @Override
036            public boolean isFilterEnabled(
037                    HttpServletRequest request, HttpServletResponse response) {
038    
039                    if (ParamUtil.getBoolean(request, _ETAG, true)) {
040                            return true;
041                    }
042                    else {
043                            return false;
044                    }
045            }
046    
047            @Override
048            protected void processFilter(
049                            HttpServletRequest request, HttpServletResponse response,
050                            FilterChain filterChain)
051                    throws Exception {
052    
053                    BufferCacheServletResponse bufferCacheServletResponse =
054                            new BufferCacheServletResponse(response);
055    
056                    processFilter(
057                            ETagFilter.class, request, bufferCacheServletResponse, filterChain);
058    
059                    ByteBuffer byteBuffer = bufferCacheServletResponse.getByteBuffer();
060    
061                    if (!ETagUtil.processETag(request, response, byteBuffer)) {
062                            bufferCacheServletResponse.finishResponse();
063                            bufferCacheServletResponse.outputBuffer();
064                    }
065            }
066    
067            private static final String _ETAG = "etag";
068    
069    }